Mold for constructing trusses



June 3, 1930. J. McKEowN MOLD FOR G OSTRUGTING TRUSSES Filed June :5o.v 1924 June 3, `1930. J. L. McKEowN MOLD FOR CONSTRUCTING TRUSSES Filed June 30. 1924 2 Sheets-Sheet 2 l/lllll/ll/l/n Patented dune-3, 1939 JOENL. MCKEOWN, 0F 1WINNETKA., ILLINOIS MOLD FOR CONSTR-UCTING .IRUSSES Application filed .Tune 3S,

This invention relates to molds for forming concrete arches, as, the top chords of trusses :for roofs, bridges and similar structures.

Broadly stated, the object of the invention is to provide a new and novel mold form for making such long span concrete arches which will be self-supporting, thus dispensing with the use of all shoring andfalse work univer- 10 sally used at. the present time, so far as I am aware, for supporting such mold forms.

A further objectof the invention is to provide a.' mold form which will be simple in construction; which will have adequate l5 strength for its designed purpose; which may quickly and conveniently be erected and removed, will be relatively light and inexpensive, and which may be used repeatedly on different jobs, instead of requiring the con- 50 struction of a new mold form for each job.

Broadly stated, I effect the objects of the invention by a mold form of truss construction, the mold proper forming the bowed top chord of the truss and the ends of said top l5 chord being connected by a tie or tension member, which forms the lower chord of the truss.

To impart adequate strength to the structure, said mold form comprises spaced side 0 members, each consisting of a plurality of superposed pieces of lumber bent to proper curvature and rigidly connected together by glue, spikes. bolts or other suitable means. As erected ltor use, the ends of the mold form proper, forming the top chord of the truss, rest upon suitable supports as the walls of a building, piers or the like, and abut against suitable rigid supports adapted to sustain the end thrust thereof under load. As shown, t-he ends of said mold form proper, abut against the upright flanges of angle` plates resting upon the supports for said top chord or mold form, which are rigidly connected by the tie or tension members forming i the lower chord of the truss. In the preferable construction shown, the tension or tie member connecting the ends oi said mold form or truss, are positioned between the side members of said mold form in such position @J that when the mold is filled with concrete,

1924. Serial No. 723,086.

the ends of said tension or tie member will become embedded therein, thus forming a permanent part of the truss or structure of which the concrete arch molded in said mold form is the top chord.

The bottom oi the space between the side members of the mold form is closed by a bottom plate secured to the under side of said side members, in any suitable manner, adapted to permit said bottom plate to be detached and removed after the concrete arch has been molded and set.

Preferably, also, the mold form proper forming the top chord of thetruss, and the tension or tie lmember thereof, are connected by suspension rods, the upper ends of which are anchored to the mold torni, preferably in such manner that they will become embedded in the concrete arch when molded, and the' lower ends of which are connected to said tension or tie member.

Where the mold form and tension member are too long to be conveniently shipped and handled as a unit, my invention contemplates maling them in sections of suitable length for shipping and handling. As erected for use, the sections of the tension or tie member are connected by turn-buckles and the sections of the mold form proper or top chord of the truss are rigidly connected by means of splice plates which overlap the abutting ends thereof and are bolted or otherwise rigidly connected thereto in such manner that they may be detached to permit removal` of the sections of the mold form after the concrete arch is poured and set.

In practice, also, the top sides of the mold torni defined by the side members are closed for a distance adjacent to opposite ends of the mold form or truss, thus preventing the concrete from flowing over the top of the mold adjacent to its ends.

The bottom plate of the mold, the top plates ot the mold adjacent to opposite ends thereof, and the splice plates which connect the sections of the side members ot said mold form, are all preferably secured to said side members so that they may be conveniently detached and removed after the concrete arch has been poured and has set.

My improved mold form also comprises the various other features, combinations of features and details of construction hereinr after described and claimed.

In the accompanying drawings, in which my invention is fully illustrated,

Figure l is a side view of a mold form embodying my invent-ion and improvements a erected for use to form the bowed concrete top chord of a truss for supporting the roof of a building, the near side of the mold form being broken away in part to show the concrete top chord of the truss with a roof supported thereon.

Figure 2 is an enlarged fragmentary side view of a section of the mold form one of the splice joints for connecting abutting sections of said mold form. l

Figure 3 is an enlarged sectional view on the line 3 3 of Fig. l.

Figure 4r is a view similar to Fig. 3 trating a modified construction.

` Figure 5 is an enlarged side view of one end of the mold form shown as erected for use.

Figure 6 is a top plan view thereof, the top plate of the mold being broken away in part; and

Figure 7 is a sectional view on the line iilus- 7 7 of Fig. 5.

In the drawings I have, purposes of clear and definite illustration, shown a meh` form embodying my invention as applied in use for forming arched top chords ef trusses for supporting the roofs of buildings, broad field of application therefor being for supporting the roofs of garages and other bnildings of relatively wide span, in which an unobstructed floor space is desired. I do not, however, desire to limit myself to this or any particular use or application, as my invention admits of a wide range of adaptation and use, of which the particular use or application shown is merely an eXemplification.

Describing the invention with particular reference to the drawings, A designates nly improved mold form as a whole. In accorcance with my invention said mold forni is made in the form of a truss, comprising a bowed top chord designated as a whole A', formed by the mold form proper, and a lower chord consisting of a tension or tie member (L, which connects the ends of said bowed top chord or mold proper A. As shown, said tension or tie member a consists of a rod, but the specific form of tension or tie member is immaterial, the rod shown exemplifying any desired or approved form of tension or tie member.

The mold form proper A consists of spaced Yside members l l, each consisting' of a ulu- 7 l l l rality of superposed pieces of lumber 2, bent to proper curvature and rigidly connected by means of glued joints, spikes, bolts er other means to form rigid unitary structures.

The side members l, l are rigidly connected in spaced relation by spacing members consisting, as shown, of bolts 3 and pipe sections l adjusted over said rods, opposite ends of which abut against the inner sides of said side members, respectively, the length of said pipe sections corresponding to the desired width of the space between said side members-that is to the desired thicknesstransversely-of the finished concrete arch forming the top chord of the roof truss. With the described construction, it is obvious that by removing the bolts 3, the side members l, l may quickly and conveniently be detached from the finished concrete arch, leaving the pipe sections d embedded therein.

If desired, my invention contemplates connecting the mold form proper r top chord of the truss A formed by the mold form, and the tension or tie member a by suspension rods 5, the spacing members consisting of the bolts 3 and pipe sections fl affording convenient means for connecting said suspension rods to said mold form or top chord, and the lower ends of'said suspension members being connected directly to said tension ortie member a.

The space between the side members l, l, is closed by a bottom 6, preferably made of boards, secured to the under sides of said side members in such manner that they may be detached and removed, if desired. As shown., the bottom (i, is secured to the side. members l, l', by bolts 7, the lower enes of which arc screw threaded. and to which two sets of nuts 8, S, are threaded, the nuts 8 exerting a clamping action on the pieces of lumber 2 forming said side members, and the nuts 8 securing the bottom (i to the lower edges of said side members. lilith the described construction, it is obvious that the bottom (i may be separately detached and removed, without disturbing other parts of the structure.

Instead of a bottom t made of boards, my invention contemplates, as a modification, a construction in which the bottom. of the mold form is closed by a sheet metal plate, the lateral edges of which rest upon and are supported by interior shoulders formed at the lower edges of said side members, which may be conveniently formed by means of pieces of lumber 2 secured to the lower edges of the side members l, I, which are wider tb an the pieces of lumber 2 from which said side members are formed and which project inwardly beyond the inner sides of said side members.

This modification is shown in Fig. Al of the drawings, in which 12, l designate the side members of the mold form proper, 2 the relatively wide pieces of lumber secured to the lower edges of said side members, 9 the interior shoulders formed by Iiid pieces 2', and l0 the bottom plate of the mold, the edges of which rest upon the shoulders 9.

As shown, the pieees'of lumber 2 are secured to the side members l2, 13, by rods 7 llt) lbU

threaded to the lower ends of which are nuts 1l, thus providing tor detaching said pieces 2 to permit the sheet metal bottom 10 of the mold to be removed.

A particular advantage of the modied construction shown in F ig. 11 is that it provides means for conveniently applying heat to the mold form to prevent concrete from freezing in cold weather. To eect this, a plate 12 is secured to the under side of the pieces of lumber 2 which, with the bottom plate 10 of the mold form, will dene a flue or passageway 13 extending beneath the mold tor-its entire length. Thus, by applying a heater to either or both ends of said* flue, the contents of the mold may he maintained at a temperature above the freezing point.

Adjacent to both ends ot the mold form proper forming the top chord A of the truss, the top sides of said mold form are closed by top plates 1.4i, which will prevent the concrete, when poured, from overflowing the sides of the mold form at the end portions thereof, which have the greatest inclination to the horizontal. As with other port-ions of the mold form, the plates 11i are secured thereto so that they may quickly and conveniently he detached when it is desired to strip the mold from the `finished arch.

The ends of the 'side members 1, 1 abut against rigid supports consisting, as shown, or angle plates l5 which are rigidly connected by the tension or tie member a. In the preferable construction shown, the tension or tie member a is positioned between the side members l, 1 of the mold form in such relation that when concrete is poured into the mold, the en ds'ot said tension or tie member will hecome embedded therein, thus, with the concrete arch, when finished, forming a root truss ot which said concrete arch is the top chord, the tension or tic member a the bottom chord and the suspension rods 5 the web members. To provide for accurately positioning the mold :torm A and to prevent displacement thereof, the sides of the angle plates 15 are preferably closed by side plates 15, hetween which the ends ot the mold form proper A are adapted to lit with slight clearance. As shown, the side plates 15 form separate pieces, but my invention contempla-tes equally forming said side plates integral with the angle plates 15.

In the drawings, B designates the concrete arch cast in the mold form proper A and which forms the top chord ot the finished roof truss.

In accordance with usual practice, the concrete arch B is reinforced and strengthened by usual reinforcing 16.

To provide tor convenient-ly shipping mold forms embodying my invention and improvements to points of use, both the side members 1, 1 of the mold forms proper A, and the tension or tie rods a may he made in separate sections, the sections of the tension or tie members being connected by turnbuclles 17 and the abutting ends of the sections of the side plates 1, 1, being connected by splice plates 18 secured to the outer sides of the side members 1, 1 in position to overlap the abutting ends of the sectionsthereot, said splice plates 18 being bolted or otherwise rigidly secured to said side members 1, 1 in such manner that they may quickly and conveniently `he detached, when it is desired to dismantle and strip the mold. p

As previously stated, apartieular advantage oit-mold forms embodying my invention and improvements is that they may be used over and over again and may conveniently be shipped from place to place for use on different jobs. y

In the practice of my invention, the parts of the mold form having been delivered on the job, the sections oi3 the top chord are assembled and connected, the angle plates 15, connected by the tension. or tie rods a, placed in position on the wall of the building or other support andthe assembled mold torni proper forming the top chord of the mold form, is placedAin position with its ends abutting against the upright flanges ot the angle plates 15 and between the side plates 15. lt' suspension rods 5 are used, these maybe enn gaged with the pipe sections l for spacing the side members l, 1 of the meld form and their lower ends connected to the tension or tie member a. The bottom plate 6 and the top plates 14 are then secured in position, and the turn-buckles 17`adi'usted to bring the member a under desired tension. The mold form being thus assembled, concrete is poured into the mold form proper and permitted to set until it becomes sutliciently strong and rigid to carry its load, whereupon the parts ot' the mol-d form proper A are detached and stripped and the concrete arch permitted to season. Having seasoned a suiiicient length of time to develop its full strength, the roof may then be laid thereon.

I claim:

l. A mold form of truss construction for use in constructing trusses having bowed top chords made of concrete, comprising a trough-shaped mold lproper comprising spaced side members which are bowed to conform to the curvature of vthe top chord of the finished trussy and which vforms the top chord of the truss formed by said mold, a tension member which connects opposite ends of said mold proper and which forms the lower chord of the truss ot whichI said mold proper forms the top chord, bolts for securing the side members ofthe form together, pipe sections adjusted over said bolts the ends of which abut against the inner sides of said side members, and suspension members the opposite ends ot' which, respectively, are secured to one of said pipe sections, and to the tension member which forms the lower chord of the truss, the relation being such that when the concrete arch is poured, said pipe sections and the upper ends otl the suspension `members secured thereto, respectively, will members each consisting of a plurality oi?A superposed pieces of lumber bent to proper curvature and rigidly secured together, means for securing said side members togather in spaced relation, and a tension member which connects opposite ends of said mold proper and forms the lower chord of the truss of which the mold propel' forms the top chord.

3. A self-supporting mold-form of truss construction for use in constructing trusses having bowed top chords made of concrete, comprising a trough-shaped mold proper comprising spaced side members which are bowed to conform to the curvature ot the top chord of the truss to be constructed and which forms the top chord of the truss formed by said mold-form, a tension member secured to and which rigidly connects opposite ends of said mold proper and which forms the lower chord of the truss of which the mold proper forms the top chord, the ends of said tension member extending into the mold cavity and being exposed therein, whereby when the mold cavity is iilled with concrete the ends of said tension member will become anchored therein and will become the lower chord ot' the truss to be constructed.

4. A mold form of truss construction for use in constructing trusses having bowed top chords made of concrete, comprising a trough-shaped mold proper comprising spaced side members which are bowed to conform to the curvature of the top chord of the finished truss and which :forms the top chord of the truss formed by said mold, a tension member which connects opposite ends of said mold proper and which forms the lower chord of the truss ot which said mold proper forms the top chord, bolts for securing the side members of the form together, pipe sections adjusted over said bolts the ends of which abut against the inner sides of said side members, and suspension members the opposite ends of which, respectively, are secured to one of said pipe sections, and to the tension member which forms the lower chord of the truss, the relation being such that when the concrete arch is poured the ends of the tension member, the pipe sections to which the suspension members are secured, and the upper ends of said suspension members will become embedded therein.

5. A truss structure embodying a temporary mold-form of truss construction consisting of a trough-shaped mold which is bowed to conform to the curvature of the top chord of the truss to be constructed and which forms the top chord of said temporary moldform truss, a tension-member secured to and rigidly connecting opposite ends of said temporary mold-form top chord, thereby forming the supporting lower chord of said temporary mold-form truss, the ends ot said tension-member extending into opposite ends of the mold cavity and exposed therein, so that said ends will be permanently anchored in the concrete top chord of the iinished truss and thus make said tension-member the permanent bottom chord of the fin ished truss.

6. Thestructure defined in claim 5, a suspension-member rigidly connected at its lower end to the tension-member and having its upper end extended into the mold cavity so as to be exposed therein, whereby when the mold cavity is filled with concrete said upper end of said suspension-member will be permanently anchored in the bowed concrete top chord of the finished truss and will become a suspension-member of said finished truss.

7. The apparatus defined in claim 5, including thrust-members which are rigidly connected by the tension-member and against which, respectively, opposite ends oi the moldform abut so that when the mold is filled with concrete said thrust-members will become the thrust-members in the finished truss with the ends of the concrete top chord abutting against said thrustmembers- In witness that I claim the 'foregoing as my invention, I aiiix my signature this th day of June, A. D. 1924.

JOHN L. MCKEOWVN. 

